To try to reduce further maternal and perinatal mortality, the standardized plan of care previously used to care for pregnant women with sickle cell hemoglobinopathies will be modified in two ways: (1) Red cells free from abnormal hemoglobins will be transfused throughout pregnancy and the puerperium to correct anemia and suppress abnormal hemoglobin production. (2) Extensive fetal monitoring will be used throughout the third trimester to identify as early as possible any deterioration in fetal well-being. A variety of studies will be carried out to determine if women with sickle cell trait are at greater risk of mortality or serious morbidity during pregnancy or when using estrogen-progestin contraceptives than are black women whose red cells do not sickle. The incidence of thrombosis, thromboembolism, and infarction will be compared for black women with and without sickle cell trait who use estrogen-progestin contraceptives. The effects, if any, of estrogen-progestin contraception on bacteriuria and urinary tract infection will be identified for black women with and without sickle cell trait. The frequency of sickling in black maternal deaths in Dallas County and the State of Texas for the past 15 years will be investigated.